Exploring the composition, phase separation and structure of AgFe alloys for magneto-optical applications

•Combinatorial thin film synthesis of bimetallicAgxFe1−xalloy for rapid materials characterization.•Correlation of composition and structure to the optical and magnetic properties of AgxFe1-xthin films.•Magnetic measurements reveal AgxFe1−xhas an antiferromagnetic phase Néel temperature of ≈120 K.•Controlled phase separation in immiscible Ag-Fe system results in tunable magneto-optical properties. Bimetallic alloys with large discrepancies in atomic radii and crystal structure typically yield systems that are highly immiscible, even at high temperatures. The AgxFe1−x binary system has limited solid and liquid solubility and thus phase separated Ag + Fe alloys should result. Furthermore, Ag has interesting plasmonic properties and Fe is a strong ferromagnet, thus magneto-plasmonic nanoparticles/films should result due to their phase separation. We have leveraged a combinatorial sputter deposition to synthesize thin films with a large AgxFe1−x (0.19